1981: electronic unit & TH350C
Thread Starter
Intermediate
Joined: Dec 2010
Posts: 27
Likes: 0
From: Catania Italy
1981: electronic unit & TH350C
Hi,
I'm sorry for my bad English.
When I bought my 1981 C3, the engine compartment was very ugly.
I removed all the tubes and wires, now it is clean and much more beautiful to see.
Of course, I replaced the carburetor, distributor, intake manifold and more.
I also removed the electronic unit, but I have a doubt: if I remember correctly, the lock-up of trans th350c is controlled by the ECU?
Trans continues to function properly?
I have to make changes or to check something?
Thanks.
Toti
I'm sorry for my bad English.
When I bought my 1981 C3, the engine compartment was very ugly.
I removed all the tubes and wires, now it is clean and much more beautiful to see.
Of course, I replaced the carburetor, distributor, intake manifold and more.
I also removed the electronic unit, but I have a doubt: if I remember correctly, the lock-up of trans th350c is controlled by the ECU?
Trans continues to function properly?
I have to make changes or to check something?
Thanks.
Toti
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Yes, you are correct, the Locku function is controlled by the CCC system. Since you have removed all the CCC components you will need to put in a lockup kit for the converter to work correctly. I believe Bowtie Overdrives sells a good kit
http://www.bowtieoverdrives.com/cata...AT&CATID=OA2A3
There are others also, see if you can google "Lockup kit"
http://www.bowtieoverdrives.com/cata...AT&CATID=OA2A3
There are others also, see if you can google "Lockup kit"
Thread Starter
Intermediate
Joined: Dec 2010
Posts: 27
Likes: 0
From: Catania Italy
Thanks for the replies.
I did not know that I can manually control the lock-up.
Now, you help me understand better.
The lock-up is like a small clutch. It combines pump and turbine, is used to not slip when the speed is uniform, if controlled by CCC system.
I have to buy only "Additional wiring for towing"? http://www.bowtieoverdrives.com/cata...php?ITEMID=344
There is written: "This optional towing kit Provides a circuit for manually controlling the lockup of the converter in second and third gear. "
It is operated manually in the second and third gear, but when I stop, I have to disable it?
How does it work?
Thanks again.
Ciao!
I did not know that I can manually control the lock-up.
Now, you help me understand better.
The lock-up is like a small clutch. It combines pump and turbine, is used to not slip when the speed is uniform, if controlled by CCC system.
I have to buy only "Additional wiring for towing"? http://www.bowtieoverdrives.com/cata...php?ITEMID=344
There is written: "This optional towing kit Provides a circuit for manually controlling the lockup of the converter in second and third gear. "
It is operated manually in the second and third gear, but when I stop, I have to disable it?
How does it work?
Thanks again.
Ciao!
Melting Slicks
Joined: Feb 1999
Posts: 2,473
Likes: 10
From: New Paltz, New York USA
I just installed a new crate motor in my 81 and I eliminated the computer. The computer did control the lock up converter, but you really do not need it. The only thing it will 
effect is your gas milage.
effect is your gas milage.
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
Thread Starter
Intermediate
Joined: Dec 2010
Posts: 27
Likes: 0
From: Catania Italy
My idea, based on what I have studied!
The TH350C need an electrical control for the converter.
If small clutch (lock up) is not activated by the computer, the converter continues to slip, then produce more heat and the engine needs more gasoline.
Right?
I repeat my question: how do I use the "Additional wiring for towing?
When I stop the car, I turn it off?
Thanks.
The TH350C need an electrical control for the converter.
If small clutch (lock up) is not activated by the computer, the converter continues to slip, then produce more heat and the engine needs more gasoline.
Right?
I repeat my question: how do I use the "Additional wiring for towing?
When I stop the car, I turn it off?
Thanks.
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Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
My idea, based on what I have studied!
The TH350C need an electrical control for the converter.
If small clutch (lock up) is not activated by the computer, the converter continues to slip, then produce more heat and the engine needs more gasoline.
Right?
I repeat my question: how do I use the "Additional wiring for towing?
When I stop the car, I turn it off?
Thanks.
The TH350C need an electrical control for the converter.
If small clutch (lock up) is not activated by the computer, the converter continues to slip, then produce more heat and the engine needs more gasoline.
Right?
I repeat my question: how do I use the "Additional wiring for towing?
When I stop the car, I turn it off?
Thanks.
http://www.youtube.com/watch?v=g7TUy6gz8HU
Sorry, couldn't figure out how to imbed the video!!
I think the additional heat thing is an internet myth, but I could be wrong.
As for your original question, you shouldn't be towing with the vette, if you need to, you're taking too much stuff!!
If you want to continue to use the lock up feature of the trans, simply wire a manual switch to turn the selonoid on and off. Originally, the ECM did that on the 81, but you can do it manually as well. You can do this where the wires go into the trans on the drivers side.
You would turn it on when you're cruising in third gear, but have to turn it off when you're coming to a stop (the ECM did this via a brake switch). If you don't, it'll act kind of like a manual transmission with the clutch engaged when you get to the stop...but won't typically quite stall the motor. It's easily done, I'd suggest a switch that lights up when it's on so you don't forget the converter is locked up.
Thread Starter
Intermediate
Joined: Dec 2010
Posts: 27
Likes: 0
From: Catania Italy
Many thanks, I had understood correctly!
If I want to spend some dollar
http://www.bmracing.com/PRODUCTS/Tra...al-speedometer
This would replace the electronic control unit, no manual control of the driver.
My C3 has the mechanical tachometer, is corrected the controller?
Thanks.
If I want to spend some dollar
http://www.bmracing.com/PRODUCTS/Tra...al-speedometer
This would replace the electronic control unit, no manual control of the driver.
My C3 has the mechanical tachometer, is corrected the controller?
Thanks.
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
You certainly could spend $200 for a controller or $2 for a switch. Keep in mind the ECM on your car controls more than just the convert lock up.
The ECM doesn't control the tach, it uses a Vehicle Speed Sensor (VSS) on the back of the speedometer, along with a manifold pressure differential (vacuum sensor) and the brake light switch to control the trans lock up. The ECM also controls spark advance, fuel mixture, and the emission control system.
Hope this helps!!
The ECM doesn't control the tach, it uses a Vehicle Speed Sensor (VSS) on the back of the speedometer, along with a manifold pressure differential (vacuum sensor) and the brake light switch to control the trans lock up. The ECM also controls spark advance, fuel mixture, and the emission control system.
Hope this helps!!
Thread Starter
Intermediate
Joined: Dec 2010
Posts: 27
Likes: 0
From: Catania Italy
Of course, I know that the ECM does other work, in fact I changed the carburetor, distributor, exhaust without catalyst and I removed all the vacuum sensors.
The engine works perfectly with a beautiful sound!
I'm sorry, maybe I can not understand me well, because of my English ...
With B&M kit, the converter works automatically, like when there was the ECM.
This kit fits with my 81? It has the mechanical speedometer?
Thanks.
Ciao (=bye)
The engine works perfectly with a beautiful sound!
I'm sorry, maybe I can not understand me well, because of my English ...
With B&M kit, the converter works automatically, like when there was the ECM.
This kit fits with my 81? It has the mechanical speedometer?
Thanks.
Ciao (=bye)
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
V8,
Your English isn't bad at all, maybe I just didn't understand what you were trying to do, I appologize.
Yes sir, the uint you provided the link for should work just fine in your 81.
BTW, Catania is in Sicily yes? I'd imagine they don't see too many C3's there!! I hope to make a trip to Italy one summer soon...perhaps next year.
Your English isn't bad at all, maybe I just didn't understand what you were trying to do, I appologize.
Yes sir, the uint you provided the link for should work just fine in your 81.
BTW, Catania is in Sicily yes? I'd imagine they don't see too many C3's there!! I hope to make a trip to Italy one summer soon...perhaps next year.
Thread Starter
Intermediate
Joined: Dec 2010
Posts: 27
Likes: 0
From: Catania Italy
Perfect!
Few C3 in Sicily, I know of only three owners, but in Italy there are many, not as in the States, but enough.
We also have a forum of passionate owners, corvetteitalia.it, some of them also write here, some very experts.
The main problem is the garage, do not know these cars, but fortunately the V8 is an old simple engine.
We need a person who repairs old cars without electronic, all the old engines are similar.
I was lucky, my mechanic is passionate about engines, and when seen my V8 ...
Obviously, I have to study for the most difficult problems, but fortunately you are!
Yes, Catania in eastern Sicily, near Taormina and the most beautiful beaches of Italy.
If you come in Italy, ask me all the information you want, I'll be very happy to help you.
Thanks.
Few C3 in Sicily, I know of only three owners, but in Italy there are many, not as in the States, but enough.
We also have a forum of passionate owners, corvetteitalia.it, some of them also write here, some very experts.
The main problem is the garage, do not know these cars, but fortunately the V8 is an old simple engine.
We need a person who repairs old cars without electronic, all the old engines are similar.
I was lucky, my mechanic is passionate about engines, and when seen my V8 ...
Obviously, I have to study for the most difficult problems, but fortunately you are!
Yes, Catania in eastern Sicily, near Taormina and the most beautiful beaches of Italy.
If you come in Italy, ask me all the information you want, I'll be very happy to help you.
Thanks.
